1. Field of the Invention
This invention is directed to novel compounds comprising metal salts of adducts of alkyl or aryl phosphorodithioic acids and a sulfurized olefin.
2. Summary of the Prior Art
Sulfurized olefins are known to be effective extreme pressure agents or load carrying additives for lubricating oils. See U.S. Pat. Nos. 3,703,504; 3,697,499 and 3,471,404.
Phosphorodithioic acids have been reacted with olefins, as disclosed, for example, in U.S. Pat. Nos. 3,646,172 and 3,350,348, and A. A. Oswald, Journal Organic Chemistry, 27, 2439 (1962). However, none of these processes are similar to the instant process nor are the compounds so produced similar to the novel adducts of this invention.
It has now been discovered that when a dialkyl or diaryl phosphorodithioic acid is added in low concentration to the unsaturated components of certain sulfurized olefins and then treated with a reactive metal salt, low phosphorus (0.1-10%), high sulfur (ca. 20% or more), low ash content products result. These products have improved oil solubility, odor, and copper strip corrosivity characteristics as compared to the sulfurized olefin and impart several desirable characteristics to organic substrates, e.g., lubricating oils, when incorporated therein. SUMMARY OF THE INVENTION
This invention is directed to organothiophosphorus compounds comprising the metal salt or complex of the reaction product of (1) a phosphorodithioic acid having the general formula ##STR1## wherein R and R' are hydrocarbyl and are the same or different with each having up to about 30 carbon atoms and (2) a sulfurized olefin. R and R' may each be alkyl of 1 to about 30 carbon atoms, aryl and alkaryl or aralkyl of 7 to about 30 carbon atoms. Accordingly, R and R' may be selected from a group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl or amyl, hexyl, ethylhexyl, oleyl, octadecyl, eicosyl, triacontyl, oleyl, phenyl, alkyl phenyl, phenylalkyl and the like, and mixtures thereof.
The sulfurized olefin contains reactive olefinic sites and may be derived from a process comprising sulfohalogenating a hydrocarbon olefin having a single double bond and having from 2 to about 8 carbon atoms per molecule with a sulfur halide selected from the group consisting of sulfur chlorides and sulfur bromides to form a sulfohalogenated intermediate and thereafter sulfurizing and dehalogenating said intermediate by treatment with an aqueous alkali metal monosulfide solution such as described in U.S. Pat. No. 3,703,504, but this class of reactant is not limited thereto. The alkali metal monosulfide solution may comprise sodium, potassium, or lithium sulfide and may contain sodium hydroxide, sodium hydrosulfide, sodium cresylates, sodium sulfate, sodium chloride, oil and ferrous sulfide. The sulfurized olefins made by variations of the process or by other process known to the art which contain reactive olefinic sites and have a sulfur content of about 20% and above may be employed in the invention. Dimethalkyl sulfides such as ##STR2## which can be formed by the reaction of methallyl chloride with an alkali metal monosulfide, alkali metal disulfide or alkali metal polysulfide may be employed in this invention. The metal of the metal salt may be selected from Groups IB, IIA, IIB, IVA, VIB and VIII of the Periodic Table.
This invention is also directed to organic compositions comprising a major amount of an organic medium normally subject to deterioration and a minor amount of an additive sufficient to impart antiwear, antioxidant, detergent, extreme pressure and antirust characteristics thereto comprising an organothiophosphorus compound in accordance with this invention and wherein said organic medium is a lubricant from among oils of lubricant viscosity, hydrocracked oils, minerals oils or fractions thereof, synthetic oils or mixtures of synthetic and mineral oils, automotive oils, gear oils and transmission fluids, hydraulic oils, waxes and greases prepared from said oils of lubricating viscosity.